package com.itheima.controller;


import com.itheima.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.UUID;

/*
* 文件上传和下载
* */
@Slf4j
@RestController
@RequestMapping("/common")
public class CommonController {

    @Value("${reggie.path}")
    private String basePath;



    /*
    * 文件上传
    * */
    @PostMapping("/upload")
    public R<String> upload(MultipartFile file){

        //file是一个临时文件，需要转存到指定位置，否则本次请求完成后临时文件会删除

        log.info(file.toString());

        String originalFilename = file.getOriginalFilename();//获取原始文件名
        String suffix = originalFilename.substring(originalFilename.lastIndexOf("."));
        //使用UUID重新生成文件名，防止文件名称重复造成覆盖
        String fileName = UUID.randomUUID().toString() + suffix;

        //创建一个目录对象(只是一个对象，不是实际存在的)
        File dir = new File(basePath);
        //判断当前目录是否存在
        if(! dir.exists()){
            //目录不存在，需要创建
            dir.mkdir();
        }

        try {
            file.transferTo(new File( basePath + fileName));
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        return R.success(fileName);
    }


    /*
    * 文件下载
    * */
    @GetMapping("/download")
    public void download(String name, HttpServletResponse response) throws FileNotFoundException {
        //输入流，通过输入流读取文件内容
        FileInputStream fileInputStream = new FileInputStream(new File(basePath+name));

        //输出流，通过输出流将文件写回浏览器，在浏览器展示
        try {
            ServletOutputStream outputStream = response.getOutputStream();

            response.setContentType("image/jpeg");

            int len = 0;
            byte[] bytes = new byte[1024];
            while ((len = fileInputStream.read(bytes)) != -1){
                outputStream.write(bytes,0,len);
                outputStream.flush();
            }

            //关闭资源
            fileInputStream.close();
            outputStream.close();

        } catch (IOException e) {
            throw new RuntimeException(e);
        }


    }
}
